Abnormal esophageal sensations, such as esophageal-related noncardiac chest pain and heartburn, are common complaints. The underlying mechanism of such esophageal nociception remains unclear. The long-term goal of our research is to elucidate the peripheral mechanism of esophageal inflammatory nociception. This proposal focuses on peripheral sensitization of vagal sensory afferents in our guinea-pig ex vivo esophageal-vagal preparation. Using this model, we have established the first direct evidence that activation of mast cells sensitizes the esophageal vagal afferent C-fiber and results in increased nerve excitability. Preliminary studies have demonstrated that several mediators and certain downstream ion channels are involved in this sensitization process. This proposal focuses on the interaction between esophageal mast cell and sensory afferent nerves. Our specific hypothesis is that mast cells in the esophageal wall play a central role in sensory neuro-modulation. Our published studies demonstrated that 1) esophageal mast cells are mainly distributed along the lamina propria with three immuno-subsets and can be activated by IgE-dependent in vitro antigen-challenge;2) activation of esophageal mast cells increases the excitability of vagal nodose nociceptive C fibers;3) mast cell preformed mediators histamine and tryptase participate in this sensitization process;and 4) sensitization of downstream TRPA1 by mast cell activation plays an important role in the modulation of nodose C fiber nerve activity. The proposed studies in the present application build on these published results and additional preliminary data to further investigate esophageal mast cell-nerve interactions.
Our specific aims are: 1) determine esophageal mast cell activation by non-IgE-dependent stimuli such as protons, neuropeptides, and certain cytokines;2) define the full range of subtypes of esophageal vagal nociceptive afferent nerves in response to MC activation;3) clarify the roles of MC mediators in activating/sensitizing esophageal vagal sensory afferent nerve subtypes;and 4) determine the downstream key ion channels in MC-mediated nociceptor sensitization, with a focus on TRPA1. The results of this study will advance the understanding of the role esophageal mast cells nerve interactions in peripheral nociceptor sensitization and will contribute to expanding therapeutic approaches to esophageal inflammatory nociception.

Public Health Relevance

Heartburn and noncardiac chest pain are the common complains where patients experience pain originating from the esophagus with or without obvious inflammation or damage to the lining of the esophagus. This project will study the underlying mechanism in which an important inflammatory cell, mast cell, increases esophageal pain nerve activity. An understanding of how mast cell activation causes this increased pain sensation will offer insight into new treatment approaches for these common but difficult managed clinical problems.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK087991-05
Application #
8499296
Study Section
Clinical, Integrative and Molecular Gastroenterology Study Section (CIMG)
Program Officer
Carrington, Jill L
Project Start
2011-07-21
Project End
2015-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
5
Fiscal Year
2013
Total Cost
$256,913
Indirect Cost
$98,325
Name
Johns Hopkins University
Department
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
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Yu, Xiaoyun; Yu, Mingran; Liu, Yingzhe et al. (2016) TRP channel functions in the gastrointestinal tract. Semin Immunopathol 38:385-96
Liu, Zhenyu; Hu, Youtian; Yu, Xiaoyun et al. (2015) Allergen challenge sensitizes TRPA1 in vagal sensory neurons and afferent C-fiber subtypes in guinea pig esophagus. Am J Physiol Gastrointest Liver Physiol 308:G482-8
Yu, Xiaoyun; Hu, Youtian; Yu, Shaoyong (2014) Effects of acid on vagal nociceptive afferent subtypes in guinea pig esophagus. Am J Physiol Gastrointest Liver Physiol 307:G471-8
Zhang, Shizhong; Liu, Zhenyu; Heldsinger, Andrea et al. (2014) Intraluminal acid activates esophageal nodose C fibers after mast cell activation. Am J Physiol Gastrointest Liver Physiol 306:G200-7
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Yu, Shaoyong; Ouyang, Ann (2011) Effect of synthetic cationic protein on mechanoexcitability of vagal afferent nerve subtypes in guinea pig esophagus. Am J Physiol Gastrointest Liver Physiol 301:G1052-8